Caution Urged on Use of Tamoxifen to Prevent Breast Cancer in Healthy Women

The merits of using tamoxifen to prevent breast cancer in healthy women are still in dispute, according to researchers at Statistics Canada.

Researchers used a computer simulation to explore a range of scenarios to attempt to identify when preventive tamoxifen therapy becomes worthwhile.

Using data from the U.S. Breast Cancer Prevention Trial, researchers examined the records of 13,388 healthy women aged 35 or older who were at high risk of developing breast cancer. The trial was stopped in October 1998 when researchers found a 49 percent reduction in the incidence of breast cancer in the tamoxifen group.

Investigators found the tamoxifen group had an increased risk of endometrial cancer, deep vein thrombosis, pulmonary emboli and cataracts. Given these side effects, they concluded that tamoxifen may only be overall beneficial for women who have a three times greater than average risk of developing breast cancer.

"Until definitive data are available, caution should be exercised in promoting the use of tamoxifen in healthy women," the researchers concluded.

Other Sources: Lancet Oncology